A vehicle may include low voltage (e.g., 12 VDC) electrical loads that may be used to operate engine actuators. The vehicle may also include electrical loads that operate at a higher voltage (e.g., 48 VDC). For example, a vehicle may include fuel injectors and oxygen sensors that operate when supplied with a low voltage (e.g., 12 volts). The vehicle may also supply electrical power to electric compressors and inverters that operate at higher voltages. Further, the inverters may supply power to electrical loads that are external to the vehicle but that are powered by the vehicle. External electrical loads may include drills, saws, and lighting used at work sites that do not have stationary grid supplied electrical power available. The vehicle's alternator may output low voltage (e.g., 12-18 VDC) based power to supply direct current (DC) to an inverter that converts DC power into alternating current (AC) power. However, the vehicle's electrical system may have to supply large amounts of current to the inverter if the inverter is capable of supplying more than a few amperes. Routing large amounts of current from an alternator to an inverter may be costly and difficult due to the need for heavy gauge wiring and vehicle packaging constraints.
The inventors herein have recognized the above-mentioned issues and have developed a method for delivering electrical power of a vehicle, comprising: supplying power to a low voltage bus via a first alternator driven by an engine and supplying power to a high voltage bus via a second alternator driven by the engine in a first mode; and supplying power to the low voltage bus via the first alternator and the second alternator in a second mode.
By providing a high voltage bus for delivering high voltage based electrical power and a low voltage bus for delivering low voltage based electrical power, it may be possible to provide low voltage operated actuators and sensors with electrical power at a same time as high voltage operated actuators and sensors are provided with electrical power. Further, since some devices such as inverters are provided with power at a high voltage via the high voltage bus, current supplied to these devices may be lowered as compared to if the same devices were operated using low voltage based power. In addition, during high load conditions, output of the first alternator and the second alternator may be combined to boost power delivered to the low voltage bus or the high voltage bus so that greater electrical loads may be supported.
The present description may provide several advantages. In particular, the approach may reduce voltage disturbances on electrical power buses. Further, the approach may reduce electrical system cost via reducing conductor size and electrical system complexity. Further still, the approach may allow a vehicle to support large external electrical loads at reduced cost.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.